There are a lot of ways you can make your site accessible, it is not really one thing. One good step is to make the site more accessible to everyone by making it responsive on mobile or smaller resolutions. Some other things you could look into for accessibility more specifically is colour contrast for text (https://webaim.org/resources/contrastchecker/), making sure images have alt-text...
Making a moving background paused by default and only activate on a button would help as well. Some people like myself have a visual impairment that makes me motion sensitive so turning off background animations help a lot.
There are a lot of ways you can make your site accessible, it is not really one thing. One good step is to make the site more accessible to everyone by making it responsive on mobile or smaller resolutions. Some other things you could look into for accessibility more specifically is colour contrast for text (https://webaim.org/resources/contrastchecker/), making sure images have alt-text...
Solaria wrote a helpful overview of examples of semantic coding https://solaria.neocities.org/template is a good place to start
Making a moving background paused by default and only activate on a button would help as well. Some people like myself have a visual impairment that makes me motion sensitive so turning off background animations help a lot.